I think you'd be better off upgrading both your CPU and GPU. The X2 6000+ is a little long in the tooth at this point. As for waiting, that depends on how badly you want to upgrade. There will always be something new on the horizon, but if you think you'll be able to afford a next-gen nVidia card when they are released, then it might be worth waiting for assuming you can hold off on gaming until then.

It's not that I wanted to wait to buy the 300 series, but wait to enjoy the resulting pricedrop. As they say with Vcards: "might as well just buy now."
As for my card, I've got no intention on replacing it... it's got more headroom than the Skydome!
anyway, can I get someone's input on which of the two cards (linked above) are better?